Electronic pulse generating circuit



Sept. 5, 1950 P. 1. KEITH-MURRAY 2,521,376

ELECTRONIC PULSE GENERATING CIRCUIT Filed April 6, 1948 Patented s le 5, 950

ths fi. 7i.- i means including -a,-rectifier and I amplified.

' m n e ents";

Patriclrilan 'Keith Murrayg CriefijScotland .Aiiiilicaumi npri 6 1 48; y 1

Th s. inven i nt o i ate provide improved-and simplified electronic circuit for generating pulses of a, desired irequency. This 1 circuit can be used forany'purpose where wave trains ofanydesired frequencyarerequiredfi v The circuit of the present invention comprises a valve oscillator-{and means whereby the negative side of the alternating current generated by the oscillator is fed back t'o the contrpl grid of resistance and capacity of 's'ucli ti-me constant a con lbina on that pulses of the generated frequency occur at the desired recurring intervals.

- The invention will be readily understood by r eference to the accompanying circuit diagram which illustrates a'preferred means for producing the recurring pulses, and wherein a valve Vl' is arranged to generate a suitable frequency by means of the circuit including the inductance L1 and condenser 01 connected to the anode and grid circuits of the valve VI. The circuit shown is a known series fed circuit including condenser.

- C3, but any circuit to produce the desired oscillations may be used. These oscillations, which would normally be continuous, are fed as shown,

I through condenser C2 and resistances R6 and R8,

to a second valve V2 for amplification. To convert the continuous oscillations into recurring pulses, a circuit is provided comprising a condenser C5, resistances RH) and RH, rectifier W,

resistance R1, condenser C4 and resistance R4.

This provides a circuit connection between the output circuit for the amplified voltage and the grid of valve Vi. A resistance R9 is interposed between the anode of valve V2 and the output transformer and thecondenser C5 is connected the junction of the parallel-connected resistance Rl l andrectifier W. As willbe seen from the V21 and con'de reSFlQ the 'o iii s v pe'atsitself." v

The'speedof the pulses thusproduceddepen ds I upon the time constant of the condenser C4 and the resistances Rl and RI I, and on the voltage developed at the junction ofthe resistances RH! and RI I.

The values given in the diagram will vary with the valves employed, those given in the diagram being by way of example only.

i I claim: 7

1. An electronic pulse generating circuit comprising a valve oscillator including an electronic valve having at least an anode, cathode and grid producing an oscillatory current at the anode of the valve, an amplifying circuit for amplifying said oscillatory current, and a circuit connection between the output side of said amplifying circuit and the grid of said oscillator, said connection including a rectifier for suppressing the positive current flowing in said connection and including a combination of resistance and capacbetween the said resistance R9 and theoutput transformer. The resistance RH! is connected to diagram, the condenser C4 is connected between I r the filament circuit of valve V1 and the resistance R1 and resistance R4.

The circuit operates, as indicated in broken lines in the diagram, as follows: The voltage generated by the valve Vi-is fed to valve V2 and Partof thevoltage now available at the anode of the valve V2 is fed through condenser C5 and resistance RIB to the rectifier .W,

umgor other rectifier suitable for the frequency involved. The rectifier is so connected as to ensure positive sides of the cycle passing to earth or LT-. As the condenser C t is connected which may be avalve, or copper oxide, or seleniity of such time constant as to negatively and increasingly charge the grid of said valve oscillator until it ceases to emit an oscillatory current, whereupon the negative charge in said connection discharges in predetermined regular' time cycles. 1

2. An electronic pulse generating'circuit comprising ,a valve generator including an electronic valve having atleast an anode, cathode and grid.

1 for producing anoscillatory current, an amplifyingvalve circuit arranged to amplify said oscillations, an output circuit for the amplified voltage, a resistor serially connected between the output circuit and the cathode of the valve, a rectifier shunted across said resistor for suppressing positive charge from the output circuit, a serially connected resistanceand capacity shunted across said resistor and rectifier with the resistance con nected to the cathode of the generator valve through said capacity, and means connected .between the junction of the serially connectedresistance and capacity for feeding a negative I charge to the grid of the valve generator in pref determined regular time cycles depending upon the time constant of said resistance and capacity.

3. An electronic pulse generating circuit comprising a valve generator including an electronic valve having at least an anode, cathode and grid for producing oscillatory current, a valve amplifying circuit for amplifying said current including a valve having an anode and cathode, a rectifying circuit rconnectedto the output fronrsaid amplifying circuit, said rectifying circuit -includ-' ing a condenser connected to the anode of said amplifying circuit, a first resistance connected to said condenser, a rectifier connected between, said resistance and the cathodes of said valves, a second resistance connected :inmara-llel with 1 ode and an output transformer, a first resistance interposed between the amplifying valve anode and the output transformer of said amplifying circuit, a rectifying circuit connected to said amplifying circuit between said resistance and output transformer, said rectifying circuit including a series-connected condenser and second resistance, a rectifier and a third resistance in parallel connection :between said series-connected condenser and-second resistance and said cathodes, a feed-back connec- Htion between the grid of said generator valve and the junction of said second resistance and said rectifier, a grid feed connection between the.

junction of said rectifier andfirsti resistance and the grid of said generator valve, a grid r charging resistance in said grid feed connection,

and a grid charging condenser connected between the grid and cathode of said generator, valve, the time-constant of .said grid charging resistance and condenser. being :such that the grid -,of ,said generator valve is I rogressively negatively charged and suddenly discharges in predetermined timecycles.

4.-..An electronic pulse'generating circuit com prising a valve generator including anelectronic vjalve having .at least ananode, cathode and grid for producing, oscillatory current, a valve amplifying circuit for] amplifying said currenthr cluding a valve having an anode and cathrectifier, a gridfee'd condenser across said feedback connection .and the cathode of said gener- REFERENCES CITED The following references are of record in the file of this patent;

UNITED STATES PATENTS Number Name Date 2,010,253 Barton Aug. :6, .1935 2,277,000 Bingley .Mar. ,17, 19,42

2430,54? Anderson Nov. 11,1947 

